Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. This is in contrast to analog electronics and analog signals. Digital electronics deals with the electronic manipulation of numbers, or with the manipulation of varying quantities by means of numbers. Because it is convenient to do so, today’s digital systems deal only with the numbers ‘zero’ and ‘one’, because they can be represented easily by ‘off and ‘on’ within a circuit.